Japanese Unexamined Patent Application Publication No. 2000-77058 discloses a battery including a pressure-sensitive current interruption device. In this battery, a tab protruding upward from an electrode assembly, a lead extending substantially linearly in a lateral direction from the tab, and the current interruption device are arranged in series to connect a conductive path between an electrode terminal and the electrode assembly. The current interruption device has a diaphragm portion joined to an upper surface of the lead. In a case where the pressure inside a battery casing rises, the diaphragm portion is inverted upward to be disjoined from the lead, thereby interrupting the conductive path. In an upper part of the battery casing, a space for the diaphragm portion to be inverted is secured.